Hello to all,
I just wanted to show a project I was proud of. It isn’t quite a robot, but it does incorporate a Basic Stamp 2 and some solenoids! 
I did this project for my 5th year in high-school. The project was very lose on the subjects, so I decided to build a compressed air engine. This is only my first prototype and due to some $ limitations, I couldn’t make it any better.
The Objective of my project was to build a prototype of an engine that could replace a conventional combustion engine. Since the compressed air engine needs lot’s of… You guessed it, compressed air, I figured I was better to plan for something like and 18 wheeler or a city bus since they have lot’s of space.
So the first step is to build air muscles. I used some 30 mm in diameter air muscles. These are roughly able to lift 150 pounds while contracting 27% of their length. To say the truth I kinda guesstimated the lift capacity because I didn’t have a way to test the muscle with 150 pounds. I used the stats from Shadow Robot (shadowrobot.com/airmuscles/techspec.shtml).
Here is my nicely done muscle 30mm (but it’s less efficient) next to the mini-muscles :
forums.trossenrobotics.com/gallery/files/1/5/4/9/157_thumb.jpg
This was also more practical for all the calculations that I will show later.
So I made a Basic Stamp 2 breadboard to control valves forums.trossenrobotics.com/showt … mp&page=15 thread)
forums.trossenrobotics.com/gallery/files/1/5/4/9/picture_362_thumb.jpg
This was a huge milestone for me, I, for the first time, managed to do something concrete with a micro-controller.
Then I made the frame. I decided to make the frame a triangle since it can’t move. For example, a square could become a parralelogram if you push hard enough. I used 6 * 24 inch metal sheets (2 inches * 24 inches * 1/8 inch). Used long screws with nuts to hold the double layer of metal and some big spacers and the corners of the triangles. These were used to hold the air muscles.
Here is the image of the frame :
forums.trossenrobotics.com/gallery/files/1/5/4/9/148_thumb.jpg
Here is the image of the air muscle that is efficient on the frame : (although very ugly)
forums.trossenrobotics.com/gallery/files/1/5/4/9/153_thumb.jpg
So I put it all together. I used 1 second intervals to open the valves. So, the engine does 1 turn in three seconds, or 20 RPM. After calculating the torque, I figured out that the engine was producing a measly 0.15 horsepower! But after reading about the combustion engine, I learned that Enrico Bernardi (who built the first combustion engine) engine only produced 0.024 CV, so it’s not that bad. My engine could produce a lot motor power, all I needed was better valve (that pass more air) because the ones I had took about 1 second to fill the artificial muscle. But those are about 500$… 
Here is a video.
So the motor breaks down at the end because I used a metal piece that was too small. (won’t make that error again!)
Calculations :
These are estimates made with the data I found.
The green cylinders in the 3D models are compressed air reservoirs made of carbon fiber.
I made three models :
18 wheelers :
I estimated with a 32 muscle motor :
Amount of compressed air : 5200 liters.
Adds a total of 850 kg to the 18 wheels.
It can run over 300km and reduces the cost of fuel of 30% to 80% depending on the truck.
forums.trossenrobotics.com/gallery/files/1/5/4/9/18_wheeler_thumb.png
City Bus :
Amount of compressed air : 3300 liters.
Adds a total of 500 kg to the bus, which is about the same weight as the hybrid buses in my city.
It can run over 200km and reduces the cost of fuel of 65% to 75% depending on the conditions.
forums.trossenrobotics.com/gallery/files/1/5/4/9/city_bus_thumb.png
UPS style truck:
Amount of compressed air : 1800 liters.
Doesn’t add any weight.
It can run over 200km and reduces the cost of fuel of 65% to 70% depending on the conditions.
forums.trossenrobotics.com/gallery/files/1/5/4/9/ups_truck_thumb.png
I gave in a 30 000 word “Rapport” explaining pretty much everything (the problem is it’s in French.)
I’m convinced that if I make a second prototype, I’d be able to make something actually useful.
What do you guys think?
Sam